Integrated charger and drive

Linear Technology has announced the LT3485 family of photoflash capacitor charger ICs which integrate complete photoflash capacitor charger and IGBT drive.



Linear says that the patented control technique of the LT3485 allows it to use extremely small “standardised” transformers. No external components are required to set the output voltage. While charging, an output proportional to the capacitor voltage is available for monitoring. Input current is tightly controlled to provide consistent charge time.



The devices operate from an input voltage of 1.8V to 10V, making them ideal for applications powered by 2 AA alkaline cells or Li-Ion single or multiple cell batteries. The LT3485-3, -0, -2 and -1 have primary current limits of 2A, 1.4A, 1A and 0.7A respectively, resulting in tightly controlled average input current of 700mA, 500mA, 350mA and 225mA, respectively. The four versions are otherwise identical.



The CHARGE pin gives the user full control of the part. Driving the CHARGE pin low puts the part in micropower shutdown. The DONE pin indicates when the part has completed charging. The LT3485 series of parts are housed in a tiny low profile 3mm x 3mm DFN package, enabling solution footprints as small as 75mm2.


The LT3485-0, -1, -2 and -3 are available from stock in a 3mm x 3mm DFN package. All are priced at $2.25 in 1,000-piece quantities and are available from stock.